A successive approximation register comprises an analog-to-digital conversion method in which the input voltage is compared with the output voltage of a sequentially programmed digital-to-analog converter. First, the most significant bit (msb) of the digital-to-analog converter is turned on and compared with an analog input. If the input is greater than the digital-to-analog output, the msb is left on. Otherwise, it is turned off. This process is repeated for all other bits in decreasing order until the least significant bit (lsb) is reached. Within sampling circuits, such as a successive approximation register operating over a wide range of voltages such as from 0–3.6 V, there are signal ranges wherein the CMOS switches used within the sampling circuits may become nonconductive and show a very high resistance due to the bulk effect. This can increase the threshold voltage, Vt, of the transistor, which increases with the bulk-to-source voltage, VBS. The occurrence of the bulk effect within the CMOS devices is highly undesirable since the sampling circuits are supposed to operate most effectively when the switches are conductive throughout the entire operational voltage range. Thus, some manner for reducing or removing the bulk effect of the CMOS switches during sampling to increase the operating voltage range of the analog-to-digital converter would be greatly beneficial.